Baltimore police on Thursday asked for the public's help in locating a mother and daughter who they said have "vanished without a trace" under suspicious circumstances.

Joanna Antionette Clark, 33, and Shariece Nicole Clark, 15, were last seen Feb. 4 at their home in the 2800 block of Round Road, in the Cherry Hill neighborhood of South Baltimore, police said.

Shariece Clark, a student at Dr. Carter G. Woodson Elementary/Middle School, was last seen about 3 p.m. Feb. 4, said T.J. Smith, a police spokesman. Joanna Clark, an employee of Goetze's Candy Co., was last seen about 11:15 p.m. on that day.

A family friend reported them missing on Feb. 7, police said.

"This is something unusual that's never happened before" with this family, Smith said.

Joanna Clark, who has six other children between the ages of 2 and 10, has "never left her children for an extended period of time," Smith said. Shariece Clark was very active on social media, but "that all went silent" on Feb. 4, he said.

Police do not have "any overt signs of a crime," Smith said, but "do have suspicions that foul play could be involved here because we have not had any information as to where these two young ladies are in an 11-day period."

He said police "don't believe this is a situation where a grown woman and her daughter just left on their own seeking shelter or just because they wanted to get away."

Smith said police do not have any persons of interest or suspects in the disappearance. They do not believe there is any connection with other recent missing persons cases in the region.

"The bottom line here is we need tips, we need information from the public, and we need any friends or confidants of either of these two young ladies to share that information with us," Smith said.

"If there is anything that they might have told you in the past that you thought was of concern, now we're telling you that it is of concern and we need that information brought forward."

Joanna Clark's other six children are safe, staying with family, Smith said.

Anyone with information is asked to call detectives at 410-396-2100 or Metro Crime Stoppers at 1-866-7-LOCK-UP. They can also text a tip to police at 443-902-4824.